1. Field of the Invention
The present invention relates to battery contact mechanisms, battery receiving structures, electric power units, electronic equipment, and pressure-contacting mechanisms, and more specifically, to a battery contact mechanism using a torsion coil spring, a battery receiving structure having the battery contact mechanism, an electric power unit having the battery receiving structure, electronic equipment having the electric power unit, and a pressure-contacting mechanism using the torsion coil spring.
2. Description of the Related Art
An apparatus such as a camera including a digital camera is often driven by a battery. Such an apparatus wherein the battery is used as the driving source generally has a structure where the battery is detachably received in a battery receiving room provided in an apparatus main body. The battery receiving room has a contact terminal and an elastic contact member. The contact terminal arranged in an electrode direction stably supports the received battery. The elastic contact member energizes the battery in the direction of the contact terminal.
Meanwhile, FIG. 1 and FIG. 2 disclose related art battery receiving structures.
In the battery receiving structure shown in FIG. 1, one end part of a coil spring (circular cone coil spring) 51 is fixed to a wall surface situated at one end side of a battery receiving room 50. A battery 52 is energized in the other side by the other end part of the coil spring 51. In addition, the end part at a side of the battery receiving room 50 of the coil spring 51 is connected to an electric lead 54 by solder 53.
Furthermore, Japan Laid-Open Patent Application Publication No. 2002-373634 discloses a battery receiving structure of electronic equipment whose objects are miniaturizing the size of the electronic equipment by making measurements of battery contact pieces contacting the electrode of the battery small and stably taking a battery power out by making a pushing force with the pressure of the battery contact pieces to the electrode of the battery constant. The battery contact pieces are formed by a torsion coil spring. An end part of the torsion coil spring works as a contact part against the electrode of the battery.
More specifically, as shown in FIG. 2, this reference discloses a battery receiving device 61-1 of electronic equipment (a camera) 61 having a battery room 65 for receiving batteries 63A and 63B. Battery contact pieces which come in contact with a positive electrode 63a and a negative electrode 63b of the batteries 63A and 63B which can be received in the battery room 65 are formed by torsion coil springs 60A and 60B. End parts of one of the torsion coil springs 60A and 60B work as electrode contact parts 60a against the electrodes 63a and 63b, respectively. The other end parts of the torsion coil springs 60A and 60B work as output terminal parts 60b for outputting electronic power of the battery. Although not shown in FIG. 2, an electric lead is connected to the output part terminal by solder and electric power is supplied from the batteries 63A and 63B to a power substrate via the electric lead. The torsion coil spring is formed by a torsion spring made of a conductive material. In FIG. 2, numerical reference 64 represents a cover of the camera and numerical reference 62 represents metal stick-shaped members. The stick-shaped members 62 are inserted into hollow parts of the coil springs 60A and 60B. Basic end parts of the stick-shaped members 62 are supported by hole forming parts formed in the cover 64 so that the stick-shaped members 62 can be rotated by an energizing force of the coil springs 60A and 60B.
However, improvements are required in the related arts shown in FIG. 1 and FIG. 2 in order to stably and precisely make contact between the electrode contact part and the battery electrode and stably supply electric power of the battery by reducing the contact resistance.
For example, in the battery receiving structure shown in FIG. 1, since the coil spring 51 works as both an energizing member and a contact member, it is difficult to simultaneously satisfy a strong energizing force and high conductivity. Because of this, an unstable state of the battery may be generated in the battery receiving room and thereby it is difficult to securely prevent an instant disconnection causing electric contact, namely a conductive state, to be broken off in an instant. In addition, as shown in FIG. 1, only the coil spring 51 works as the energizing member. Hence, if a sufficient energizing force is attempted to be generated at the coil spring, a metal material having high conductivity cannot be used as the spring material. Furthermore, in this case, the distance from a part where the battery electrode and the battery contact member are in contact to a part where an electric lead of the battery contact member is pulled out or part soldered with a print board becomes long and thereby the value of resistance becomes large. As a result of this, it is not possible to efficiently take the battery electric power out.
In the structure shown in FIG. 2, since the torsion coil works as both the energizing member and the contact member, it is difficult to simultaneously satisfy a strong energizing force and a high conductivity. In order to obtain high conductivity, for example, it is necessary to apply a nickel plating or gold plating to phosphor bronze. However, it is difficult to heighten a spring constant by using such a metal material. In a case of spring steel that is normally used, although it is possible to obtain a high spring constant, it is difficult to secure high conductivity.
In order words, under the structure shown in FIG. 2, although the above-mentioned instant disconnection problem can be solved because strong energizing forces can be obtained by the torsion coil springs 60A and 60B, it is difficult to obtain high conductivities by the springs 60A and 60B. Furthermore, under the structure shown in FIG. 2, it is necessary to arrange members combined by the torsion coil springs 60A and 60B and the stick-shaped member 62, corresponding to each of the batteries 63A and 63B. Hence, the structure is complex and it is difficult to miniaturize the entire battery receiving structure.